1. Field of the Invention
The present invention generally relates to a pipe joint, and particularly to a pipe joint for connecting pipes through which the likes of hot water, antifreeze, liquid heat medium or vapor passes.
2. Description of the Related Art
As an example of a conventional pipe joint for connecting pipes typified by those of heaters and calorifiers, through which the likes of hot water, antifreeze, liquid heat medium or vapor passes, there is a pipe joint comprising a joint body, tube-side connector formed on one end of this joint body to be connected to a pipe tube, and header-side connector formed on the other end of the joint body to be connected to the header; i.e., a pipe assembly joint.
This type of pipe joint is expected to satisfy five conditions; namely, that it has (1) chemical resistance against residual chlorine contained in the service water, (2) resistance against oxidization/deterioration due to oxygen dissolving in high-temperature service water, (3) resistance against hydrolysis in hot water, (4) mechanical strength that does not deform at a water pressure of 7 kg/cm2 (10xcx9c15 kg), and (5) impact resistance capable of withstanding the water hammer phenomenon. Thus, in this type of pipe joint, the joint body, tube-side connector and header-side connector are formed from metals such as brass or copper. Moreover, the joint body and tube-side connector, and, the joint body and header-side connector are integrally formed by brazing, respectively, in order to satisfy the aforementioned conditions.
This pipe joint, however, has shortcomings of becoming expensive and heavy as it is manufactured by processing metals. Further, as there is no degree of freedom upon designing the shape of the pipe joint, it is necessary to add a separate component with secondary processing when providing additional functions thereto. This further increases the manufacturing cost. There is also a possibility that hot water or vapor would leak from the brazed portion of the pipe joint. Particularly, it the pipe is made of resin, the deterioration of the resin is accelerated by the contact between the metal and resin.
In addition, for example, the pipe joint and header are fastened with a separate component such as a fastening clip. This results in work inefficiency and increased costs due to separate components being required. It is also possible that a user will lose such components. Moreover, upon connecting a pipe tube to the pipe joint, a dedicated jig is used. Here, it is necessary to provide a flange to the pipe joint in order to determine the position of such jig and secure the pipe tube. This flange, however, is formed either by carving a pole having a large diameter or by attaching an E ring or C ring to the pipe joint, and there is a problem of much time and labor being required and of increased manufacturing costs.
Thereby, considered was forming the pipe joint from resin, which is inexpensive, easy to process, and light.
As the aforementioned resin, for example, used may be polyacetal, polyamide, polyphenylene sulfide, and so on. Nevertheless, the maximum temperature in which polyacetal can exhibit chemical resistance against residual chlorine contained in the service water is 60xc2x0 C., and there is a shortcoming in that it may not be used for hot water or steam exceeding 80xc2x0 C. Further, polyamide has shortcomings of dimensional change due to water absorption, decrease in mechanical strength, generation of hydrolysis or oxidization/deterioration with hot water of 80xcx9c90xc2x0 C. Moreover, although polyphenylene sulfide has superior chemical resistance, it lacks the impact resistance capable of withstanding the water hammer phenomenon. In addition, it also has a shortcoming in that a structural design utilizing elastic flexture in order to realize a snap fit is not possible. As described above, currently, there is a problem in that a resin fulfilling the aforementioned five conditions does not exist.
The present invention was devised in view of the foregoing conventional problems, and an abject thereof is to provide a highly reliable leak-proof pipe joint which is superior in workability, inexpensive and light, superior in resistance against chlorine and oxygen contained in hot water or vapor, resistive against hydrolysis in hot water, superior in mechanical strength and impact resistance, and thereby capable of withstanding deformation due to water pressure or water hammer phenomenon
In order to achieve the aforementioned object, the present invention provides a pipe joint for connecting pipes through which hot water, antifreeze, liquid heat medium or vapor passes, comprising: a main body; and a connector for connecting the main body to a pipe; wherein at least either the main body or connector is formed from one type selected from a group consisting of resin it which thermoplastic elastomer is added to polyphenylene sulfide, polysulfone, polyphenyl sulfone, polyphthalimide and polyetherimide, and the main body and connector are formed integrally.
In other words, by forming at least either the main body or connector from one type selected from a group consisting of resin in which thermoplastic elastomer is added to polyphenylene sulfide, polysulfone, polyphenyl sulfone, polyphthalimide and polyetherimide, which are superior in chemical resistance and impact resistance at high temperatures, provided is a pipe joint which is superior in workability, inexpensive and light, superior in resistance against chlorine and oxygen contained in hot water or vapor, resistive against hydrolysis in hot water, superior in mechanical strength and impact resistance, and thereby capable of withstanding deformation due to water pressure or water hammer phenomenon.
Moreover, by integrally forming the main body and connector, the manufacturing process of brazing etc. required with conventional metal pipe joints will no longer he necessary. In addition, this integral structure can also prevent water leakage from the brazed portion and, particularly, there will be no contact between the metal and resin,
The pipe joint according to this invention may also be structured by forming at least either the main body or connector from resin in which at least one type among glass fiber, mineral or thermoplastic elastomer is added to a type selected from a group consisting of polysulfone, polyphenyl sulfone, polyphthalimide and polyetherimide, and the main body and connector are formed integrally.
The pipe joint according to this invention may also be structured by forming at least either the main body or connector of resin in which at least one type among glass fiber or mineral is added to resin in which thermoplastic elastomer is added to polyphenylene sulfide, and the main body and connector are formed integrally.
In other words, by adding glass fiber, mineral or thermoplastic elastomer, which are superior in impact resistance, to a type selected from a group consisting of polysulfone, polyphenyl sulfone, polyphthalimide and polyetherimide, which are superior in chemical resistance and impact resistance at high temperatures, obtained is resin extremely superior in chemical resistance and impact resistance. Therefore, the pipe joint in which at least either the main body or connector is formed from this resin will be superior in workability, inexpensive and light, superior in resistance against chlorine and oxygen contained in hot water or vapor, resistive against hydrolysis in hot water, superior in mechanical strength and impact resistance, and thereby capable of withstanding deformation due to water pressure or water hammer phenomenon.
The pipe joint according to this invention may also be structured by forming at least either the main body or connector of resin in which at least one type among glass fiber or mineral is added to resin in which thermoplastic elastomer is added to polyphenylene sulfide, and the main body and connector are formed integrally.
According to this structure, the pipe joint will be superior in workability, inexpensive and light, superior in resistance against chlorine and oxygen contained in hot water or vapor, resistive against hydrolysis in hot water, superior in mechanical strength and impact resistance, and thereby capable of withstanding deformation due to water pressure or water hammer phenomenon.
The thermoplastic elastomer nay be added to polyphenylene sulfide at a ratio of more than 5% and less than 20%. If the additive ratio of the thermoplastic elastomer to polyphenylene sulfide is less than 5%, there tends to be difficulty in obtaining superior impact resistance. Contrarily, if the additive ratio of the thermoplastic elastomer to polyphenylene sulfide is more than 20%, there tends to be difficulty in obtaining superior chemical resistance. The natural mechanical strength of polyphenylene sulfide may also be lost.
Glass fiber or mineral may be added to one type among polysulfone, polyphenyl sulfone, polyphthalimide and polyetherimide at a ratio of more than 5% and less than 50%. If the additive ratio of glass fiber or mineral to polysulfone, polyphenyl sulfone, polyphthalimide or polyetherimide is less than 5%, there tends to be difficulty in obtaining superior impact resistance. Contrarily, if the additive ratio of glass fiber or mineral to polysulfone, polyphenyl sulfone, polyphthalimide or polyetherimide is more than 50%, there tends to be difficulty in obtaining superior chemical resistance. The natural mechanical strength of polysulfone, polyphenyl sulfone, polyphthalimide or polyetherimide may also be lost.
Glass fiber or mineral may also be added to resin in which thermoplastic elastomer is added to polyphenylene sulfide at a ratio of more than 5% and less than 50% If the additive ratio of glass fiber or mineral to resin in which thermoplastic elastomer is added to polyphenylene sulfide is less than 5%, there tends to be difficulty in obtaining superior impact resistance. Contrarily, if the additive ratio of glass fiber or mineral to resin in which thermoplastic elastomer is added to polyphenylene sulfide is more than 50%, there tends to be difficulty in obtaining superior chemical resistance.
Thermoplastic elastomer may also be added to one type among polysulfone, polyphenyl sulfone, polyphthalimide and polyetherimide at a ratio of more than 5% and less than 20%. If the additive ratio of thermoplastic elastomer to one type among polysulfone, polyphenyl sulfone, polyphthalimide or polyetherimide is less than 5%, there tends to be difficulty in obtaining superior impact resistance. Contrarily, if the additive ratio of thermoplastic elastomer to one type among polysulfone, polyphenyl sulfone, polyphthalimide or polyetherimide is less than 20%, there tends to be difficulty in obtaining superior chemical resistance. The natural mechanical strength of polysulfone, polyphenyl sulfone, polyphthalimide or polyetherimide may also be lost.
Further, an engaging member for detachably engaging with a step member formed on the pipe may be provided to the main body. this engaging member and main body may be formed integrally.
According to this structure, the pipe joint can be securely fastened to the pipe one-handedly, and the work efficiency is improved. Moreover, separate components for fastening the pipe joint and main body will not be required.
Further, a step member for detachably engaging with an engaging member formed an the pipe may also be provided to the main body.
The step member may be a flange formed at the end of the main body, and the flange and main body may be formed integrally.
The engaging member may comprise an engagement pawl at the tip thereof for engaging with the step member, and may have a structure wherein the engagement pawl elastically retreats in the direction away from the step member upon passing the step member, whereby the engagement pawl is restored after passing the step member.
An engagement release member for releasing the engagement of the engagement pawl and step member may be provided to the base end of the engaging member.
Further, a flange for determining the connective position of the pipe may be integrally formed on the main body.